Self-cycling valve

Abstract

A self-cycling valve including a main valve and an operator valve. The main valve comprises a body having an inlet port, an exhaust port, and two outlet ports, and valve elements for controlling communication between each outlet port and the inlet and exhaust ports. The operator valve has a valve member movable between two extreme positions for controlling operation of the valve elements of the main valve. In one extreme position of the valve member, one outlet port of the main valve communications with the inlet port and the other outlet port communicates with exhaust; in the other extreme position of the valve member, the outlet port connections are reversed. The valve member of the operator valve cycles between its extreme positions in response to fluid pressure levels at the outlet ports of the main valve. A spring-biased, pivoting detent urges the operator valve member into each of its extreme positions, the spring force being applied to the detent along a line transverse to the direction of movement of the valve member, so that the biasing force decreases during the movement of the valve member from each extreme position toward its midpoint of travel and increases during movement of the valve member from the midpoint of its travel to the other extreme position. Pistons at opposite ends of the operator valve member respond to fluid pressures at the outlet ports, respectively, for moving the valve member back and forth between its two extreme positions.

I claim: 
     
       1. A self-cycling valve including a main valve and an operator valve, the main valve comprising:   (a) a main valve body having fluid pressure inlet and exhaust ports and first and second outlet ports, and   (b) main valve means within the body for controlling communication between each outlet port and the inlet and exhaust ports, and   the operator valve comprising:   (c) an operator valve body, the interior of the body communicating with the fluid pressure inlet port and with the main valve means in the main valve body,   (d) a valve member movable within the operator valve body, between first and second extreme positions, for controlling operation of the main valve means, the first and second outlet ports communicating with the inlet and exhaust ports, respectively, when the operator valve member is in its first extreme position and the first and second outlet ports communicating with the exhaust and inlet ports, respectively, when the operator valve member is in its second extreme position,   (e) means responsive to an increase in pressure above a predetermined value at the first outlet port for moving the operator valve member from its first extreme position to its second extreme position, and means responsive to an increase in pressure above a predetermined value at the second outlet port for moving the operator valve member from its second extreme position to its first extreme position, and   (f) means for resiliently biasing the operator valve member into each of its extreme pistons, said resilient biasing means including a detent pivotally arranged with respect to the operator valve member and resilient means biasing the detent along a line of force transverse to the direction of movement of the operator valve member, the detent being arranged at an acute angle to the direction of movement of the operator valve member when that member is in either of its extreme positions, and the detent moving through a position in which it is perpendicular to the direction of movement of the operator valve member as the latter moves from each of its extreme positions to the other, whereby the force of the biasing means tending to hold the operator valve member in each of its extreme positions decreases during the movement of the operator valve member from that extreme position to the midpoint of its travel and increases during the movement of the operator valve member from the midpoint of its travel to the other extreme position.   
     
     
       2. A self-cycling valve as defined in claim 1 wherein the detent is a pin rounded at both ends, the operator valve member having a pocket slidably accommodating one end of the detent, and a bearing block having a pocket slidably accommodating the other end of the pin, the resilient means urging the bearing block toward the operator valve member. 
     
     
       3. A valve comprising: a valve body,   a valve member movable within the body between two extreme positions for controlling fluid flow through the valve body, and   means for resiliently biasing the operator valve member into each of its extreme positions, said resilient biasing means including a detent pivotally arranged with respect to the valve member and resilient means biasing the detent along a line of force transverse to the direction of movement of the valve member, the detent being arranged at an acute angle to the direction of movement of the valve member when that member is in either of its extreme positions, and the detent moving through a position in which it is perpendicular to the direction of movement of the valve member as the latter moves from each of its extreme positions to the other,   whereby the force of the biasing means tending to hold the valve member in each of its extreme positions decreases during the movement of the valve member from that extreme position to the midpoint of its travel and increases during the movement of the valve member from the midpoint of its travel to the other extreme position.   
     
     
       4. A valve as defined in claim 3 wherein the detent is a pin rounded at both ends, the valve member having a pocket slidably accommodating one end of the detent, and a bearing block having a pocket slidably accommodating the other end of the pin, the resilient means urging the bearing block toward the valve member.